While toilet manufacturers have made strides in reducing the volume of water required to flush a toilet, the standard amount of water held in the standard toilet tank may be more than needed for light waste loads. Many toilets in the world use much more than the current standard and an improvement in volume flushed can save a great quantity of water. Considerable water can be saved if a light flush option is provided by the tank flushing system.
There remains a need for a two level flushing mechanism that provides control and permits the user to choose the appropriate flush duration within a single handle mechanism. While many people may be reluctant to hire a plumber to re-plumb their toilet, a device that is retrofittable in the same simple manner that a new flapper is installed would likely be readily accepted and self-installed by most.